CVE-2026-3870

Name of the Vulnerable Software and Affected Versions Zyxel VMG4005-B50B versions prior to 5.13(ABRL.5.4)C0

Description A buffer overflow in the UPnP AddPortMapping() command allows an adjacent attacker to cause a temporary denial-of-service (DoS) condition, which is a state where a system becomes unavailable to its intended users, specifically affecting the UPnP function of the device.

Recommendations Update to a version newer than 5.13(ABRL.5.4)C0. As a temporary workaround, restrict access to the AddPortMapping() command to minimize the risk of exploitation.